According to Florida Territorial Acts 1826, 5th session, page 151 Jefferson County was created from Leon County. It became effective January 30, 1827. 

This county was named for Thomas Jefferson, the third President of the United States of America, who served from 1801 to 1809. It's location between the panhandle and peninsular Florida, it is often referred to as the "keystone" of Florida.

Forts of Jefferson County

https://en.wikipedia.org/wiki/List_of_forts_in_Florida 

Fort Roger Jones

(1839), Aucilla (Ocilla Ferry), north of US 90.

Fort Noel

(1839–1842), south of Lamont on the Aucilla River, six miles (10 km) northwest of Fort Pleasant in Taylor County. Also known as Fort Number Three.

Camp Carter

(1838), near Waukeenah.

Fort Welaunee

(1838), a settlers' fort on the Welaunee Plantation near Wacissa. Fort Gamble (1839–1843) was later established here.

Fort Aucilla

(1843), two miles (3 km) south-east of Fort Gamble, southwest of Lamont, between the Aucilla and Wacissa Rivers. Also spelled Ocilla.

Fort Wacissa

(1838), a settlers' fort located south of Wacissa on the Wacissa River, west of Cabbage Grove.